Internal combustion engine charge forming apparatus



May 15, 1945. R. M. ANDERSON 2,375,883

INTERNAL-COMBUSTION ENGINE CHARGE FORMING APPARATUS Original Filed June16, 1939 24A: Mini/0M 2:114:15! Mai/a IM "My 01:

atented May i5, 1945 INTERNAL COMBUSTION ENGINE CHARGE FORMING APPARATUSRaymond- M. Anderson, Detroit, llfich, assignor to Evans ProductsCompany, Detroit, Mich, a

corporation of Delaware Original application June 16, 1939, Serial No.

279,394, now Iatent No. 2,323,639, dated July 6, 1943. Divided and thisapplication November 20, 1942. Serial No. 466.275

14 Claims. (o1. 123-119) The present invention relates to internalcombustion charge forming apparatus .and this application is a divisionof applicants copending application Serial No. 279,394, filed June 16,1939, now Patent Number 2,323,639 for Internal combustion engine chargeforming apparatus and relates to such apparatus and particularly todevices combined with an engine to reduce detonation, or knocking byadmitting an anti-knock fluid such as exhaust gas under certainconditions, such as under heavy loads,

Various other charge forming features and combinations and suchanti-knock devices are claimed in this parent application, but theantiknock apparatus or devices to supply exhaust gas only at full loadconditions are claimed therein in combination with a, particular enginefuel supplying means, namely, means to supply the intake conduit with ahigh temperature super rich mixture of oil and a small part of the totalair supply, whereas the invention of this divisional application relatesto such anti-knock devices per se or in combination with ordinaryengines without regard to such special fuel supplying means.

The objects of this invention are to provide improved internalcombustion engine charge apparatusincluding simple and dependable meansto prevent or reduce knocking of the internal combustion engine underheavy load conditions. Other and more specific objects, features andadvantages will be apparent from the following specification, thecorresponding drawing, and the appended claims.

In the drawing, in which like numerals are used to designate like partsin the several views throughout;

Figure 1 is a general view showing in elevation part of an embodiment ofthe whole specific charge forming and regulating apparatus of the aboveidentified parent application as it appears installed on or applied to aconventional, present-day, automotive vehicle, gasolineengine, withconduit 39 shown diagrammatically and showing a first form or embodimentof my anti-knock device applied to such an engine;

Figure 2 is a wholly diagrammatic and spread out view of some of themajor portions of the whole specific charge forming and regulatingapparatus of my above identified parent application and corresponding toFigure 1, this view showing generally 01' schematically the epnnectionsbetween the several parts but vnotaccu- ,rately showing relativepositions or th*relative vertical levels of the parts and also showingin more detail the first embodiment of my antiknock device as applied;

Figure 3 is a partly diagrammatic view showing a modified form or asecond embodiment of. an installed anti-detonation unit according to myinvention; and

Figure 4 is a sectional View of still another modified form or a thirdembodiment of an antidetonation unit, according to my invention.

In general, the anti-detonation unit of this invention may be applied toor used in combination with any of various sorts of internal combustionengines for vehicle, marine or stationary use having spark ignition,exhaust and an intake manifold or conduit means with a carburetor or thelike to supply any desired fuel in the proper mixture ratios into thisintake conduit and more particularly to conventional or present-daytypes of gasoline engines, such as are now commonly used in trucks andpassenger automobiles. In order to completely disclose one particularapplication of my improved anti-detonation apparatus as specificallydisclosed in parent case and to give a better understanding of its useand interrelation and combination with the other parts of an internalcombustion engine, I have included herein thoseportions of thespecification and drawing of my above identified parent application,which relate more directly to my anti-knock device, and have brieflysummarized the rest of the equipment of the parent application, yet Iintend to include by reference herein the balance of this parentapplication, in order to give the desired and complete understanding ofthis specific embodiment.

However, as indicated above, it is to be understood that this divisionapplication is not .intended to be in any wise limited to thisparticular type of engine or fuel feeding system since it will begenerally ap arent and will appe r from the present application that theimproved antidetonation device of the present invention may be ofgeneral utility and used in combination with various conventional sortsof internal combustion engines, as indicated above.

As shown as a whole in Figure 1 and as shown,

schematically in Figure 20, the improved charge forming and regulatingapparatus is applied to a conventional type asoline engine 2 having aninduction intake conduit including 'the intake manifold 3 and an exhaustconduit including the exhaust manifold 4. The intake conduit includes acarburetor unit I which, as illustrated herein, maybe of the down drafttype. The engine is provided with the usual air cleaner H2 mounted abovethe carburetor. A compact, fiat, vaporizer-heater unit or heat exchanger5 is jacketed and heated by exhaust gases conveyed thereto from theexhaust manifold by a pipe it, the used exhaust gases being carried backto the exhaust conduit by pipe i. Pipes 6 an i may be used to supportthis vaporizer-heater unit.

The main unheated air-fuel mixture is carried from the carburetor unit Ito the heater by horizontal pipe connection 8, and the hot super richmixture is conducted from the heater to the carburetor mixing chamber bythe slightly lower horizontal pipe connection 9, which is preferablymade of aluminum, aluminum alloys or the like, as discussed hereinafter.

In the present invention, the major part of the engine's air supply issucked down through the intake conduit (comprising the riser, the mixingchamber, and the intake manifold) in the usual fashion, while a smallproportion (preferably about 5% and less than of the total air supply isdrawn through a separate passage, the hot mixture-contacting portions ofwhich are all of aluminum or the like, and which includes connections 8and 9 and the substantially horizontal, tortuous, mixture-heatingpassage in the heater 5.

In general, I have provided a suitable Venturi means 65 located near theentrance 8 to this passage, together with suitable light and heavy fueljets (not shown) to supply either light or heavy fuel from the adjacenttwo reservoirs of a suitable multi-fuel carburetor I, thus either of thetwo fuels is metered and mixed with the air stream in passage 8, andthis super rich mixture is heated to a. high temperature so that thesprayed fuel is partly gasified, partly vaporized, and the balancefinely divided. For the sake of simplicity, this condition ishereinafter referred to as vaporized.

It is believed impractical to thoroughly gasify all of the oil or toreally crack all Of the heavy hydrocarbons in an apparatus of this type.Only enough air is used in this rich mixture to effectively carry thefuel and to hold enough heat to effectively vaporize the main fuelsupply and to keep it in this condition in the intake manifold. It isimportant that only a small portion of the total air supply is heated toa pre-dctermined temperature so that the volumetric efficiency of theengine will not be materially reduced. Such a reduction in volumetricefiiciency, with its attendant decrease in power and torque, would occurif it were attempted to heat sufficiently all of the engines air supplyto permit the use of'low grade fuel, or if even a small proportion ofthe total air were heated to too high a temperature. Also, too high atemperature, tending to distill or crack the heavy fuel, will producecarbon and gum deposits; while, on the other hand, too low a temperaturewill cause crankcase dilution from the unvaporized globules of heavyfuel.

It may be noted in connection with the use of heavy fuel, such as oil,in a conventional gasoline type engine, that it has been previouslyproposed to heat the liquid oil (without any appreciable quantity ofair) in a small passage or elsewhere and then to spray it into theintake conduit where it is supposed to be vaporized and mixed in aventuri or the like. Such systems are impractical, if not commerciallyimpossible,

since it is not possible'to get enough heat into the liquid oil itselfso that it will vaporize sufficiently when discharged into the intakemixing chamber. On the other hand, if sufficient heat is added to thisliquid oil so that it is partly gasifled or vaporized in its heatingpassage, then the metering will vary widely with small temperaturechanges and as alternate charges of liquid and vaporized oil come alongthe passage.

Any sudden increases in the richness of the fuel mixture from thevaporizer-heater 5, and particularly the collection or trapping of apool of liquid fuel which is later sucked into the intake conduit at aperiod of high vacuum (for example, when the throttle is suddenlyopened), are highly objectionable since they cause smoking, carbon andgummy deposits, tend to choke the engine, to produce crankcase dilution,and reduce economy. Hence the uniform vaporization and supply of therich, heated air-fuel mixture and the provision of a propervaporizer-heater and connections therefor which have no traps or thelike, are particularly desirable.

As is well known, the actual temperatures of the exhaust gas in themanifold of ordinary gas oline engines vary within wide limits (about600 degrees F. to nearly 1450 degrees F.) under different speed and loadconditions so that the amount of heat available to the exhaust heaterfor the super rich air-fuel mixture varies widely. Accordingly, it isimportant that the quantity of exhaust gas made available to the heaterunit be regulated not only in accordance with temperature but inaccordance with engine speedload conditions, which may be represented byexhaust gas flow rate. If the rich heated mixture of air and heavy fuelis not heated to a high enough temperature, there will be excessive andobjectionable crankcase dilution due to lack of vaporization of theheavy fuel condensation.

Also, too low a temperature is apt to cause smoking. O n the other hand,too high a temperature for this mixture will reduce the volumetricefficiency, as noted above. It has been found that a mixture temperatureof about 400 degrees F. is best when using oil or similar heavy fuels,although this temperature may be varied from about 375 to 500 degreesF.- When using gasoline, even the cheaper, poorer grade with low octanerating, in this super rich heated mixture, good results may be obtainedwith lower mixture temperatures. For example, a temperature as low as280 degrees F. can be used, with best results at about 350 degrees F.However, the above mentioned 400 degrees F. temperature will be foundsatisfactory for either type of fuel.

It has been found that the better distribution obtained because of thepredetermined amount of heat added with this rich heated mixture morethan offsets the expected slight decrease in volumetric efliciency sothat higher torques have been obtained. Also, this better distributiontends to reduce detonation.

Another reason why it is important to regulate the temperature of themixture in the vaporizer-heater unit 5 is that it is necessary in orderto secure proper over-all air-fuel ratios under different loadconditions and the corresponding temperatures of the exhaust gas in theexhaust manifold 4. For example, an increase in temperature of thevaporizer-heater will cause an expansion of the air in the mixturepassage therein and an even greater expansion of the.

fuel particles, which will tend to reduce the vacuum in this passage andthus reduce the suction on the main fuel jet (not shown here) so thatthe mixture will become leaner. The converse asvaasa will, oi course,occur if the temperature drops suddenly. "Thus it will be apparent thatchanges in temperature will affect the metering adversely and,accordingly, the over-all fuel ratio and the economy.

Referring again to the more specific, complete disclosure in the parentapplication, it will be apparent that the flow of the exhaust gas fromthe exhaust manifold Al to the exhaust pipe 93 may be all or in partdiverted through a by-pass circuit consisting of a pipe connection itthrough the jacket surroundin the vaporizerheater 5, through connectionil and pipe 2', this diversion being controlled by a suitable thermostatically regulated valve unit comprising the unbalanced valve 99,which is on a shaft which also carries the inertia weight wheel [Hi lcarrying the ofiset and adjustable weight 103 to bias valve Q9 towardits closed or heating position, this weight it?) being secured in anyone of sevadjusted positions by bolt 8% which may be received in one ofseveral holes (not shown here). The valve 99 is also actuated towardopen or closed position by a suitable bi-metallic element, as will bewell understood in this art.

Referring further to Figure 1, the carburetor l is of the multi-fueltype and in addition to supplying either light or heavy fuel, such asgasoline or oil, to the intake to the vaporizer 5. This carburetor ialso embodies means to suppor gasoline for acceleration, for idling, andfor the conventional compensating flow. It Will be noted that these arealways on gasoline and will operate concurrently with the main superrich air fuel mixture from the vaporizer which discharged into thethroat of a multiple-Venturi set 58 through pipe 9. These more. detailedfeatures will be seen more clearly in the incomplete schematic Figure 2which also shows the exhaust gas inlet 53 and discharge fitting ll forthe vaporizer 5, the conventional air cleaner M2, the entrance to theintake conduit above the carburetor, the conventional choke at and,above the choke, but below the air cleaner, the pipe i3 3 to supply airto a special form of economizer its, the pipe '53 to supply air to theventuri, the entrance pipe 8 and the pipe M5 to bleed air to thenon-illustrated but conventional gasoline idling system, which as usualsupplies the idling gasoline into the manifold adjacent the throttleplate H3 through conduit lfiti,

Just below the choke and upstream from the multiple Venturi set whichincludes the parts 68, Sill-A and 62), l have shown the conduit meansH673 to inject gasoline for acceleration and this conduit i6? isperiodically supplied with gasoline by wholly conventional means whichare well known in present day carburetors and include a suitablyactuated pump supply by gasoline from the reservoir in the two bowlcarburetor i. This metered oil or metered gasoline is supplied throughjets from one of the two valves in carburetor units l through conduit63-455 to the Venturi unit 85.

The suitably metered compensating flow of gasoline is led into theVenturi set 69 by conduit means i 55.

It will also be noted that Figure 2 shows certain details of theeconomizer l28, including pipe wt, to supply vacuum to actuate thepiston valve 929 which controls the admission of -air into the intakemanifold through the annular passage Bi. and the ports M2. This featurein particular may, of course, be eliminated, if desired, and in generalwill be understood as emphasized above that the above described detailsor specific parts are not to be considered as part of this invention,except insofar as they supply one specific installation.

Referring now to the operation of this particular embodiment, as shownin the parent application, it will be seen that for starting, asdisclosed in the parent application, I have provided entirely theconventional carburetor units or parts, including an accelerator pump,the idling system and a compensator metering system and jet to supplythe intake manifold or its mixing chamber with these auxiliary flows ofgasoline concurrently with a supply of the super rich mixture of a smallpart of the air with either oil or gasoline as delivered into the mixingchamber venturi 69 by pipe t. Obviously, these particular details arenot essential to the present invention.

In order to reduce detonation or knocking at high load and speedconditions, particularly where operating temperatures are high, a novelanti-detonation unit (of which three forms are hereinafter described)may be employed, which may admit a small amount of exhaust gas into theintake manifold at the time of detonating conditions under the control.of the throttle itself or in response to exhaust manifold and intakemanifold pressures, which are a measure of the engine load-speedconditions.

One form of anti-detonation unit is shown more or less schematically inFigures 1 and 2 in which the housing l'lll has a narrow valve guidingportion ll i, the enlarged upper end of which-is connected by pipe H2 tothe intake throttle, and

which also has the pipe or conduit ll?) connect-' ertia damped toprevent flutter. When the valve is closed it will be up against thevalve seat ill and close off communication from the exhaust connectionH3. Generally speaking, this valve unit is either on or off, and it willbe apparent that the piston I15 isactuated by and is responsive to thealgebraic sum of the exhaust pressure and the intake manifold pressurewhen the valve l'l l is off its seat ill; that is, the exhaust pressureis aided by the weight of the valve in holding it open while the intakemanifold vacuum is tending to lift the piston H5 up to close the valve.No springs or the like are used for biasing a valve of this type sinceit would be difficult, if not impossible, to make a spring which wouldstand up under the very high temperature and hard service encountered ina unit of this type. It will be apparent that by properly proportioningthe weight of the valve, the piston area, and the size of theconnections, this valve can be made to open only at full load conditionsof the engine; and it will be responsive to the load-speed conditions ofthe engine since at full load conditionsthe intake manifold vacuum isquite low, and the exhaust pressure is high. In addition, the exhaustpressure will increase with the speed of the engine. Pipe connectionsI12 and H3 and the valve housing I10 itself will cool the exhaust gaswhich is carried from the exhaust manifold to the intake manifold toreduce the loss of volumetric efficiency due to the highly expanded hightemperature exhaust gases. If additional cooling is desired, it will beobvious that a suitable heat exchanger or cooler can be added to thisunit.

It will be apparent that the heavy valve l'l i will normally beheld onits seat Ill to shut on any exhaust gas flow by the intake manifoldvacuum action on the piston I15 and overcoming the weight of parts I75and I'M.

With a valve unit of the types disclosed herein, it has been founddesirable to admit inert gas up to about of the volume of the air-fuelcharge for full or nearly full loads only. This will eliminate orgreatly reduce the knocking which is more of a problem when the hotengine is runnin and the upper end of this housin 210 has an opening forthe valve actuatin rod 28I'which carries a pivoted member 280 whichcontains a slot 279 cooperating with a pin 218 which is fixed on or withrespect to the throttle I I3. This pinand-slot lost motion connection isso arranged that the valve is lifted from its'seat only at or near fullload throttle openings so that exhaust gas will be admitted only atthese conditions when detonation would be apt to occur.

A preferred form of this anti-detonation unit is shown in Figure 4 inwhich the valve housing 318, which may be made in the form of a simplecasting or otherwise, is tapped for the exhaust manifold pipe orconnection 313 and the intake manifold pipe or connection 312. The upperend of the valve housing 310 is closed by plate 382 which may be securedon suitable shoulders by the upper edges of the housing being peanedover or the like. This plate is vented to atmosphere at 316, and aslight amount of gas may leak through this vent 316. The plate or diskvalve element 376 may be circular and slightly smaller in diameter thanthe circular housing 310 so that it has a loose or sloppy fit therein.The disk valve 314 need only be heavy enough to insure its seating whenthe engine is being started. When in its normal low position resting onthe valve seat 3", it will be apparent that this disk valve 314 closesoff communication to the central It will be apparent that when.

of the valve itself. As noted above in connecthe disk valve 314 is inits upper or open position,

it is subjected to the value of the exhaust pressure minus the value ofthe manifold suction and, in addition, to its own slight weight. Note,however, that when the valve is opened, the resultant of these twopressures acts over its whole area.

The anti-detonation units of both Figures 3 and 4 have one advantageover the unit of Figure 2 in that they will not be open when the engineis first started and thus permit a flow of exhaust as into the intakemanifold, which will make starting more diilicult. It is also noted thatthe units of Figures 3 and 4 may include a cooling fluid, if desired.

Although the foregoing description is necessarily of a detailedcharacter, in order that the invention 'may be completely set forth, itis to be understood that the specified terminology is not intended to berestrictive or confining and that various omissions and rearrangementsor modifications of parts may be employed without departing from thescope or spirit of the invention as claimed herein.

I claim:

1-. In combination, an internal combustion engine embodying an exhaustconduit and intake conduit having fuel supply means and anti-knock meansadmitting a small amount of exhaust gas from the exhaust conduit to theintake conduit only at full load conditions and comprising a gravitybiased, normally closed valve arranged to hold itself closed when theengine is not running, a valve housing, and connections so that saidvalve is responsive to the intake vacuum and the exhaust pressureopposing each other.

2. In combination, an internal combustion engine embodying an exhaustconduit and intake.

conduit having fuel supply means and anti-knock means admitting a smallamount of exhaust conduit to the intake conduit only at full loadconditions and comprising a heavy gravity biased and inertia dampedvalve element, a valve housing, and connections so that said valve isresponsive to the intake vacuum and the exhaust pressure acting inopposition.

3. For use with an internal combustion engine embodying an exhaustconduit, an intake conduit, and a throttle, an anti-detonation unit foradmitting a small amount of exhaust gas from the exhaust conduit to theintake conduit during knocking conditions and including connections anda normally closed, gravity biased valve, and means including a 10stmotion connection connecting said valve to be operated by said throttle.

4. For use with an internal combustion engine having an exhaust conduitand an intake conduit, an anti-detonation unit for admitting a smallquantity of exhaust gas from the exhaust conduit to the intake conduitduring knocking conditions and comprising a heavy, inertia damped valveelement gravity biased toward open position and means to hold said valveclosed during normal running conditions responsive to and actuated bythe intake conduit vacuum.

5. For use with an internal combustion en-,

. tion connecting said valve to be opened by said throttle only whenmoved to its substantially fully open position.

6. For use with an internal combustion engine embodying an exhaustconduit and an intake conduit, an anti-detonation unit for admitting asmall amount of exhaust gas from the exhaust conduit to the intakeconduit only at full load conditions and including cooling connectionsand a normally closed, gravity biased valve responsive to and actuatedby th intake vacuum and the exhaust pressure opposing each other.

7. For use with an internal combustion engine having an exhaust conduitand an intake conduit with a throttle, an anti-detonation unit foradmitting a small quantity of exhaust gas into the intake conduit beyondthe throttle comprising an on-ofi type valve and means tOhOld said valveclosed during normal running and to open it only under heavy loadconditions.

8. In combination with an internal combustion engine having an exhaustconduit and an intake conduit with a throttle therein, anti-detonationmeans connected to admit a small quantity of exhaust gas into the intakeconduit after the throttle during knocking conditions comprising anon-ofi? type, heavy, inertia damped and gravity biased valve and meansto sold said valve closed during normal running conditions and to openit only under heavy load conditions.

9. For use with an internal combustion engine having an exhaust conduitand an induction intake conduit with a throttle therein, an antiknockunit to admit a small quantity of exhaust gas into the intake conduitbeyond the throttle only during knocking conditions comprising an on oroil type heavy valve, inertia damped and gravity biased to closedposition so that it is closed when the engine is not running and duringnormal running conditions and means to open said valve only during fullload conditions.

10. For use with an internal combustion engine having an exhaust conduitand an induction intake conduit, an anti-detonation unit to admit asmall quantity of exhaust gas into the intake conduit under heavy loadconditions comprising a casing having valve guide means therein and anupwardly facing valve seat therein, a large area free disk type valvereciprocable in said casing, having a' loose fit in said casing and itsguide ,means, and gravity biased to rest on and close off said valveseat when the engine is not running and during normal runningconditions, said casing being vented to atmosphere on the other side ofsaid valve, the space within said valve seat being connected to theintake conduit and said casing having. means to subject the larger areaannular outer portion of the same under 'side of the valve to theexhaust pressure,

whereby, when closed, the smaller area of, the inner portion of the areaof the under face of the valve is subject to the intake vacuum and thelarger area of the outer portion of the area of the under face issubject to the exhaust pressure modified by the leakage from said loosefit and saidvent and, when open, the entire under face of the valve issubject to the algebraic sum of the intake and exhaust pressuresmodified by the leakage from said loose fit and said vent.

11. For use with an internal combustion engine having exhaust andinduction intake conduits, an anti-detonation unit including a freereciprocating valve means biased to closed position when-the engine isnot running and during normal running conditions, and means to actuatesaid valve to admit exhaust gas to said intake conduit only during heavyload conditions, including a piston area and connections to expose onepart of said area ,to the intake vacuum when the valve is closed and toexpose all of said area to the algebraic sum 0f these two pressures whenthe valve is open.

12. For use with an internal combustion engine having an exhaust conduitand an induction intake manifold, an anti-detonation unit, comprising anon or off type valve to admit an anti-knock substance into the intakemanifold only during knocking conditions, and means to actuate saidvalve responsive to the intake manifold vacuum and the exhaust pressureacting in opposition.

13. For use with an internal combustion engine having an exhaust conduitand an induction intake conduit with a throttle therein comprising ananti-detonation unit comprising a valve casing having connections to theexhaust conduit and to the intake conduit beyond its throttle. meansincluding on or off type valve therein to control the admission of'ananti-knock substance into the intake manifold beyond its throttle. andquick acting means to actuate said valve to hold it closed during normalrunning conditions and to open it only during heavy load conditions.

14. For use with an internal combustionengine having an exhaust conduitand an induction .intake manifold with a throttle, an anti-detonationunit for admitting a small quantity or exhaust gas into the intakemanifold beyond the throttle during knocking conditions comprisingpassage means to connect to said exhaust conduit and to said intakemanifold beyond the thottle, and control means in said passage means toprevent exhaust gas flow therethrough during all normal runningconditions and to permit exhaust gas flow therethrough only during heavyload conditions.

' RAYMOND M. ANDERSON.

